Dust spraying apparatus



July 21, 1942. J. H. MoRRow DUST SPRAYING APPARATUS Filed May 15, 1941 fSTATE g novel apparatu`s`- of lpredetermined quantity of vdust maybesprayed Patented July 21, 1942 Dusrs'PRArrNc rBRA'rUs J oseph' H.Morrow, Hckendauqua, Pa., assigner to f vFuller Company, Catasauqua,Pa., a corpora-v .,tion oIrDelawarev I U,

.This invention relates to dust spraying ordis` tributingapparatus,infwhich'thejmateri'al to be sprayed'is delivered from a`supply hopper to an entraining air ,stream vbypow'e'r driven means.

More V'particularly the invention relates to `ra this type vwhereby auniform or distributed at substantial v,velocity to surfaces remote fromthe Idust supply hopper. An exam'- ple o f'the use ofthe new 'apparatusis the sprayvisionofan apparatus forspraying nely dividedmaterial',usually in dust form, which is superior ,to the priorapparatus inthat the delivery of material is constant and` plugging ofthe discharge line is'avoided'-f The new apparatus is compact so' thatitc'anbe mounted on a standing of such rmaterial as rock dust in mines,such as coal mines; to coat thedepositsfof necoal dust in ordertoiprevent explosions andfit may also be "employed to'advantage inthespraying of ins ecticidal dust for Vthe preservation of crops, etc. Theaccumulation of. finek combustible dust, such as coal dust;up on thewalls, 'in crevices, and

upon the'floors of minesypresents a real Asource of danger to the minersin that this accumu'v lated'material, under certain conditions, issubject to spontaneous combustion, while under certain otherconditions,l

the imine, a cloud of the fine materialvmay be- Such 'as VA'carried toan area wherea spark from'voperating machinery will cause its explosion.y To avoid the possibility ofsuch explosions, it is the practice toIc'oat all interior" surfaces of the mine draughts through ingly, be

. ygeous when ard mine caran'ditisf capable of delivering material topoints from 100 to 500 feet distant. "While the apparatusof the'invention may be employed for spraying various types'of dust for manydifferent'purposeait is especially advantaused in mines'. An embodimentof the invention suitablefor mine use will, accord\ i1lustrated anddescribed in detail. For a better understanding of the inventionattention is directed to the accompanying drawing'illustrating one formof the invention. In

v the drawing- FigureV 1 is'a plan viewof the improved apparatus. f

", Figures'Z andf3 are sectional views taken on lines 2- 2, and'3-3,*respectively of Fig. 1.

charge valve plate; 25,

' Figurefll is an enlarged-elevation of the dis- Figures 5 "nd6 aresectional views taken on lines .fi-I5v and li--B of Figure 2, Figure 6being enlarged to show certain details.

With'a thin film of: rock dust, which adheres to Y i vbe seen t`ocomprise a hopper I0 having sloping 'the surfaces because of the4natural dampness" present.' Manyof the tunnels, cracks, andcrevicesextending from, the main mine passageways are'too small toaccommodate the passage of cars means which" might be used to` carry 0rother 'dusting' equipment, and itis, therefore, necessaryv from thedusting appa-4 toy disc harge .the'dust ratusat a sufficient velocitytoproject' the' dust `Heretofore;various formsl of apparatus have -beenemployed to sprayv or distribute dust for the purposes set forth, butthe available Iequipment has not'been wholly satisfactory.v'Iheefliciency of the prior equipment is excellent whenit may be'brought close to the surfaces to which the dust is to beapplied, but ithas' been found, for example, inthe spraying of the required surfaces inmoved.

AThe present invention is ydirected to the prof particles to theinaccessible surfaces. vWhere' y' Referring t'cthe drawing, theapparatus will side walls I I and a bottom I2. A bearing housing I3extends from' the rear end Vwall of 'the hoppr,-near itsbottom, andspaced along the length faste ned to a suitable support for front endWall of 'the hopper is providedwith van opening- I5 through which the ymateriallpasses'to'a barrel I6 secured in alignment 'with theopening I5by collar I1 and bolts Y seals ythefhopper from 'the bearing housing,

I8. v,The barrel I6 is positioned inaxialr alignment with the bearinghousing I3, and av ,rotatable shaft I9, supported by ia front bearing2U, which and a rear bearing 2I,'exten ds through the hopper andinto'the barrel I6 concentrically therewith. Azshaft sem z2 inthetearing 2o is connected to 'a source of "air supply by a short pipe 23ywhereby a constant flow of air along the shaft in the c' vdirection ofthe hopper is maintainedto prevent 50 coal inines,4 that large portionsof rtlfie surfaces V requiring treatment arefat points remote from j thetunnelsyth'roughy which an apparatus may be leakageffof materialinto'the bearing housing. The shaft may bedriven in any suitable manner,as b y an electric motor (no t'shown) having `its rotor connected to theend of the shaft extendingbeyond the bearing 2 I That porticnof theshaft I9 within the hopper carries screw nights 24 of uniform pitch and,upthrough the mixing chamber outlet 39. 'I'he outon rotation of theshaft, the nights advance let 39 is provided with threads yIII for theatmaterial from the hopper through opening I5. tachment of a hose line(not shown) o1' the de- The nights 24 terminate short of the opening I5sired length to direct the stream of entrained and a second series ofscrew nights 25 on that 5 dust to the point of application, the pressureportion of the shaft within the barrel I6 cause maintained within thesystem being'suniclent to the material to be advanced through the barrelovercome the resistance of the hose line and cause to itg disqh'fg'gniAsfmor dgflypshqwn iny ischargf" it: the material `at the end thereofwith Figssfl'a-a'rrd V2v; this'secondserie's* of s'crw nightsubst'antialftorce." f is of slightly decreasing pitch in the direction10 To assist in the control of the quantity of of the terminal night 26.The shaft and3`s'orwf..-` material passing into the barrel I6, and alsoto nights terminate short of theidischargeendof reducmthe power requiredto rotate the shaft the barrel to afford a seal space itowhicnt'h 'I9to"a"""minimum, the material supply in the material iscompactedztmresist:the* anticipated vhopper .mayf be aerated. For thispurpose, air back pressure conditloni'f f onglesdlsextending through theside walls of The barrel I6 terminates in an air mixing Pthe*hopper areprovided. These nozzles are chamber 21 into which the-materialisdischarged.;y i; A.spar/e351,longitudinallyo1 the hopper and have dis- Acollar 2s having a center'bo'r'eof'thesxne iii- "charge ends lying closeto the screw nights 24. temal diameter as the barrel is atffhdr'tdthe.an illheinozzles are connected to the compressed air .the l and Lformsits, terminalyfox'.'dis-` 20 ,Supply through pipes 38, andv to controlthe now Y l" '2.9y-` cally' car'ved by` .,'f air in the nozzles nearestthe opening I5, these fnozzles are provided with valves 42, so thatadelimitted. The control valves 42 shown are for y regulation of the airnow through the nozzles 4I 'Y the nearest the opening I5, but it will beobvious that i To d St position; agftimes f such valves could be used tocontrol the now of hen DaliSllDDl Qf; ,111. ,tlilissics'ffrom the airthrough all of thenozzles. v au15] 'Whenffhe'fspplyjiglerratie, the Theoperation of the apparatus is as follows: "M With the apparatus mountedupon a suitable i carriage, the hopper is nlled with a supply of dustmaterial having the desired characteristics. The vslide valvecontrolling the opening to the barrel is set at the desired position;and a source of and mixing chamber nozzles so that the material thescrew and the outer endof r 28 may be in the hopper adjacent theadvancing screw is .,,.variedbyinsertionptrpneqi-more seal rings 3|,aerated and a substantial pressure is ldeveloped v32' between the collarandthel end of the barrel. in the chamber. `As there is -no discharge ofOrdinarily the sea1ed.,sp ace provided without us- 40 material from thebarrel at this time, the pres- A)irigtli'e 4ringsA,is.silulfl,cien ermltoperation sure within the chamber causes the nap valve overf.- widelijiiirig'eoi'fpr 4ssur nd the use of seal at the discharge end of thebarrel to be tightly ringstoeirtend the length@ seal space isnecessealed and a reverse air blow through the barrel .sary onlyunereextreme `conditions. to the hopperis prevented. The air nowing into"tegof'uimhgfgev (gf-the meel-19,1V from 45 the material through thehopper jets immediately Shing I5 is controlled aerates the material inthe lower portion of the 1 l 4 l, ffplate valve 33, secured hopper andthe rotatable shaft may be connected tof'ui iniiefiaceof, thefront endwail through to its Source of power as soon as a steady now of whi Wematerial isdi charged. 'I'he plate valve air is obtained. The aerationof the material in is`"rastened ,the endw'auin the desired position 6othe hopper permits the use of a much ,lighter readil ,femovable means34` extending motor for driving thlsshaft, thus resulting in through'siiit'abl holesin the wall and plate. The l a saving in motor 00st andpower. Upon rotation plateisfprvided with a vertical row oi' spaced ofthe shaft. the uniformpitoh Screw ishts on holes` 3.5,a e hside wherebyvertical adjustment that DortiOn 0f the Shaft Within the hODPer Cause*'fjte pflat "yfe accomplished, val-y the 5.5 the vmaterial in thebottom of the hopper to be eriing is through which the matemoved forwardand enter the open end or the l A cut-out portion 36 in the botbarrelwhere it is compressed somewhat by the ate of a diameter slightlygreater screw nights on that portion of the shaft and Iaineter of theshaft I9 permits the is compacted in the seal space at the vend of thebeflowered over the shaft at the point en barrel between the shaft endand the nap valve. y e two series of screw nights. When As materialcontinues to now through the barrel, l pe g I5 is partially closed bythe valve increase of material in the seal space gradually platgfnly aportion of the material moved forbuilds up a pressure against the valvesuine-lent rdby" 'the nights 2l will pass therethrough, to overcome theresistance offered by the weight 'niainder striking the plate and moving65 of the valve and the back pressure, and the valve lly in the hopperwithout substantialcomopens to discharge the material into the mixingchamber where it is mixed and entrained with pressanf Streams of airunder pressure are directed into the air and caused to now to the pointof applie 'mixing chamber 2'I by a pair of convergent cation. Duringdelivery of the dust, the rate of 31 which are connected to 'a suitable70 discharge may be varied at will by regulation of of positive airsupply (not shown) by hoses the now of air through the hopper jetsadjacent ems enectsenlcient mixing andentrainso that -the dual controlanorded by the slide koi! (the, dust received'in the chamber, and a 75valve and the valves controlling the hopper jets permits a widevariation in the discharge rate.

'flllielturbulence resulting from the impinging the point where thematerial enters the barrel,

"air str now or entrained dust is maintained cate control o1' theaeration at this point is percompressed air is connected to the hopperJets' 'l1 An apparatus for spraying dust materialv which comprises thecombinationof a hopper to receive asupply ofthe dust material, abarrelcommunicating with the .hopper through an opening in its front wall, arotatable shaftv exseries o1' screw flights havinga, decreasing pitchtoward the terminal'end of the'shaft to cause the dust'rfnaterialadvanced to, be compacted adjacent tending through the hopper andintothe barrel, y

the shaft terminating short of the discharge end of the barrel, a seriesof screw flights on .that

portion of the shaft within the hopper to advance the material to thebarrel', said screw flights 'terminating short of the front Wall of thehopper, a second series of screw flights Orrthat i portion of the shaftwithin the barrel to advancel the materialfto its discharge end, saidsecond discharged dust material, means for injecting' compressed airinto the chamber wherebythedust material is admixed and entrained intheair, means to direct the entrained material to desired points ofapplication, aeration jets extending into the hopper and having theirdischarge ends adjacent the screw flights to direct compressed air intothe material toy reduce the density of the material advanced by thescrew, and valve means to regulate the ilow of air through the jets.

2. An apparatus for spraying dust material which comprises thecombination of a hopper to receive a supply of the dust material, abarrel communicating with the hoppery through an opening in its frontwall, a rotatable shaft extending through the hopper and into thebarre1,"

the shaft terminating short of thedischarge `end- 'of the barrel, aseries of screw flights on that portion of the shaft within the -hopperto advance the material to the barrel, said screw iiights terminatingshort of the front wallof the hopper, a second series of screw nights onthat portion of the shaft within the barrel to advance the material toits discharge end, said second toward the terminal end of the shaft tocause the dust material advanced to be compacted adjacent the terminalflight, a mixing chamber communicating with the barrel to receive thedischarged dust material, means for injecting compressed air into thechamber whereby lthe dust material is admixed and entrained in the air,means to direct the entrained material to desired points of application,aeration jets extended into the hopper and having their discharge endsad jacent the screw flights near the' communicating opening to thebarrel, and valve means to regulate the ow of air' from the jets,whereby the rate at which the material enters the barrelgmay -60 becontrolled.

3. An apparatus for spraying dust material which comprises thecombination of a hopper to receive a supply of the dust material, abarrel communicating with the hopper through 'an vthe terminal'iiight, amixing chamber communicatinggwith the barrel to .receive'the'dischargeddust material, means forlinjectingcompressed air'into the chamberwhereby `the Vdust/material is adinixed and entrained in the air, meansto direct the entrained material to desired points of application,aeration jets .extending into the hopper and having 'theirdischa'rgeends adjacent the screw flights to direct; Vcrnpressed 'air into thematerial to reducethe density of, the material advanced by the screw,valvelm'eans to regulate .15 series of screw flights having a decreasingpitch l the flow of air through the jets, a. slide valve removablycarried by the hopper'fto restrict. the

l. openingyto the barreL'and means toyarythe po- Y sition ofthe valvewhereby the rate of ilow of the material from the hopper into theIbarrel is further controlled". c

4; apparatusvforl` spraying d ust material which-"comprses'thecombination of a -hopper having sloping side walls toreceive a supply ofthe dustv material, a bearing housing extending from the lower portionofv the rear endwall of the hopper, a barrel communicating with thehopper through an openinginitsfront wall, the bearing housing andthebarrel being in axial alignment, a rotatable A'shaft mounted in bearingsinthe housing and Aextending through the hopperl and. into the barrel,aseries of screw flights of .uniform pitch on that portion of the shaftwithin the hopper to advance the material toward' the-barrel, s'aidscrew flights terminatingv short ofv the front wall `of the hopper,` asecond series of screw flights on that portion of the series ofscrew'iiights having a decreasing pitch .45

,shaft within the barrel to advance the material to its discharge end,said second series of screw flights having a decreasing pitch toward theter- `-min'al end ofthe shaft to cause theI dust material to becompactedadjacent the terminal flight, a mixing` chamber integral with theterminal end of the barrel and communicating therewith to receve thedischarged dust material, a collar secured to the end of the, barrel andpositioned within the mixing chamber,-a flap valve normally sealing thedischarge end of the barrel and pivotally carried by the collar,convergent nozzles communicating with the mixing chamber adjacent thedischarge end of the barrel to direct streams. of compressed air theretowhereby the dust material is admixed and entrained in the air, meansconnected to the mixing chamber'to direct the entrainedmaterial-therefrom, to desired points of application, aerationjetsextending intothe hopper and having Atheir discharge ends longitudinallyspaced'adjacent the screw flights -to direct compressed air into thematerial to reduce the density of the` material advanced by the screw,valve meansv to regulate the flow of air through the jets,a slide valveadjustably carried by the hopper to restrict the opening to the barrel,and means'to vary the position of the valve whereby the rate of thematerial from the hopper'is/f-urther controlled.

5. An apparatus f'orv spraying dust material which comprises thecombination of a hopper for holding. a supply of the material, a'barrelcommunicating with .the hopper through an opening in the wall thereof, arotatable shaft extending through the hopper and into the barrel, theshaft terminating short of the end of thebarrel remote from the' hopper,spaced series of screw ights on the shaft within the hopper and barrel,respectively, for advancing materialv from the hopper into and throughthe barrel, the series of auf I which comp for Edding

